A typical vehicle lamp assembly comprises a housing portion with a reflector containing a rear-loaded filament light bulb and a lens affixed to the open end of the housing. This construction is rather large in size and takes up a considerable amount of depth when housed in a vehicle. As vehicle designs have changed over the years to create more compact vehicles with improved gas mileage, designers have sought ways to reduce the size and space requirements for housing a lamp assembly.
In order to reduce the size of a lamp assembly, vehicle lamp designers have begun to use light emitting diodes (LEDs) instead of filament bulbs. In a LED lamp assembly, LEDs are mounted or placed within a lamp housing and a lens is then affixed and sealed to the open end of the lamp housing. Because LEDs are much smaller and produce less heat than a filament bulb, a lamp assembly containing LEDs is much smaller (thinner) in size. Thus, LED lamp assemblies allow vehicles to be further reduced in size, because less volume is required in the vehicle to house each of the lamp assemblies. Unfortunately, the current method of assembling LED lamp assemblies prevent further reduction in size of the vehicle lamp assembly because of the elements needed to both seal and affix the lens to the lamp housing.
FIG. 1 shows an exploded view of a LED lamp assembly 2. As shown in FIG. 1, LED lamp assembly 2 comprises a lens 3 having a lens leg 4 around die periphery of the lens. Lamp housing 5 has a lens leg channel 6 located around the periphery of the lamp housing. FIG. 1a shows a cross-sectional view of an almost fully assembled LED lamp assembly 2 along line A—A of FIG. 1. As shown in FIG. 1a, lens leg channel 6 is designed and of sufficient depth and width to accept lens leg 4 and the large amount of sealant required to assemble the lamp assembly. Lens leg 4 and lens leg channel 6 are of sufficient size to provide enough surface area for a sealant to both attach and seal lens 3 to a lamp housing 5.
Further, referring back to FIG. 1, lamp assembly 2 comprises at least one attachment means, such as two clips 8 and two notches 9 on lamp housing 5. Clips 8 fit into notch 9 and on top of lens 3 so that the lens and lamp housing 5 are held together. The attachment means is only used for a period of time sufficient enough to allow the sealant to cure. An LED array 12 is mounted in lamp housing 5 and is covered by lens 3. As used herein, the term “LED array” means a plurality of LEDs arranged on a single circuit board or a plurality of circuit boards.
FIG. 2 shows a flow chart of the steps that comprise the method of assembling LED lamp assembly 2. As shown in step 40, LED array 12 is mounted to lamp housing 5. Step 41 comprises placing a sealant, such as a silicon sealant, into lens leg channel 6. In step 42, lens leg 4 is inserted into lens leg channel 6 so that lens leg 4 seats to the bottom of lens leg channel 6. As shown in step 43, clips 8 are attached to two notches 9 on lamp housing 5 and to lens 3. In this manner, two clips 8 hold lens 3 to lamp housing 5 until the sealant is allowed to cure. As shown in step 44, once the sealant cures around lens leg 4 and in lens leg channel 6, the sealant will attach and seal lens 3 to lamp housing 5 to form LED lamp assembly 2. To accomplish both the attaching and sealing purposes, it will be appreciated by one skilled in the art that a large amount of sealant is required to be used. Further, it will be appreciated by one skilled in the art that the lens leg has to be large enough to provide enough surface area to allow the sealant to both attach and seal the lens to the lamp housing. Moreover, the lens leg channel must be large enough to hold the lens leg and the large amount of sealant required to attach and seal the lens to the lamp housing. The large amount of sealant, the length of lens leg 4 and the depth of lens leg channel 6 are required to both seal and attach lens 3 to lamp housing 5. It is the required amount of sealant, the size of the lens leg and the size of the lens leg channel that prevent designers from obtaining any further reduction in the size of vehicle lamp assemblies.
Accordingly, it is desirable to provide a method of assembling a thin lamp assembly for vehicles that can further reduce the size of the vehicular lamp assembly. In particular, it is desirable to eliminate the lens leg, eliminate the lens leg channel and reduce the amount of sealant needed to seal and attach the lens to the lamp housing.